George Tomlinson, the post-war education secretary, declared that politicians should leave exams to the teachers because ‘the minister knows nowt about curriculum’. Today, however, the curriculum seems to be in a state of permanent revolution. The new GCSEs, for example, are marked on a nine-point scale: a grade of 7 or above indicates what used to be an ‘A’. For every five students who hit the 7 threshold, only one will get 9, the top mark. How employers are meant to understand this is another question.

The GCSE overhaul is the latest of a series of reforms, started by Michael Gove seven years ago, which are intended to ‘restore confidence’ after years of grade inflation. During the Labour years, ministers denied that exams were getting easier. They insisted that the proportion of As had risen over the years because the quality of education had improved. If that were true, Britain would not now be the only country in the developed world where numeracy among 16-24-year-olds is lower than it is for 55-65-year-olds.

The cost of educational failure can be seen all around. A recent survey asked adults what, if a worker on £9 an hour was given a 5 per cent pay rise, his new salary would be. Almost a quarter were unable to answer, even with the help of a calculator. Another government survey found that only a quarter of adults would pass GCSE maths, and barely half would pass GCSE English with grade C or above.

The problem is, at its root, political: too much of the debate in Westminster revolves around who gets into Oxbridge. It is the great English disease: an elitist obsession with elite (especially private) education, which results in a deficit of government interest in every-thing else. So we end up with the world’s best secondary schools and universities, but remain a country where most young people think Sherlock Holmes was real. In an economy in which knowledge fairly quickly translates into earning power, this poses obvious problems.

Each year, there is a great fuss about A–level and GCSE results, but no one talks about Btecs. These are vocational qualifications offering specialist learning, which were sat by an extraordinary 250,000 students this year. Btecs are normally assessed by coursework, rather than externally marked exams, and since they offer an anomalously large number of the ‘points’ needed for university, they have come to be seen a way to game the system, to secure more ‘points’ for less work. Few politicians pay any attention.

A quick search on social media for the word ‘Btec’ establishes the exam’s reputation among young people. It has become slang for a bad version of something good: so Liverpool can be derided as a ‘Btec version of Manchester’, while football supporters accuse their rival teams of employing ‘Btec versions’ of their players, and so on. Yet this obloquy has not stopped the dramatic rise of the exam’s popularity. Pearson, which runs the exam, boasts that a quarter of those accepted to university have at least one Btec.

The grade inflation for Btecs has been eye-watering. The Higher Education Funding Council’s latest report looks at the proportion who take top marks in Btec and A-level. It found that the proportion of pupils granted Distinction, the highest Btec grade, has doubled over ten years. Universities are aware of this, which is why they far prefer pupils with A-levels — who of course tend to come from more affluent backgrounds. Another study, released earlier this year, found that only 15 Btec students were accepted at the four most selective universities in 2015.

Not that anyone in Westminster seems to mind. Most MPs will have sat O-levels or GCSEs, and A-levels, and their children will do the same. Btecs tend to be taken by other people’s children. The neglect of the non-elite education system counters social mobility. Yet the government has done very little about Btecs; indeed, its latest plan is to categorise them as ‘academic’ qualifications.

Michael Gove approached the subject of education with great purpose, direction and energy — which have been rather lacking since he left the job. School reform came to be seen as a trademark mission of the Cameron government, which perhaps explains why it now seems to have dropped off the agenda entirely. May tried to revive the tired argument about grammar schools. But having failed to win a majority in the election, she will not be able to lift the ban on expanding them. Maybe this will push her to complete the reform mission started by Cameron.

The mission is not even halfway complete, as teachers can attest. There is no point in creating vocational T-levels without the feeder curriculum to support the success of such exams. There is no point in making mathematics tougher at A-level if so many pupils abandon the subject after GCSE. Nor is there any point in making adjustments to Btecs if their purpose is so ill-defined.

The risk is that the government will lose momentum, or interest, in the school reform agenda. With five years to go until the next election, there is a case for a wholesale review to take stock of the progress made so far and to outline the next steps. As the electorate gently reminded Mrs May at the last election, there is more to education policy than Oxbridge and grammars. The Conservatives can be proud of much that has been achieved so far, but they need to finish the job.